Orthogonal frequency division multiple access (OFDMA) is a technique whereby a frequency spectrum is divided into relatively narrow band-width sub-channels. In the 802.11 family of standards, OFDMA is proposed to address communications efficiency in dense (e.g., a large number of devices) environments. For example, each wireless station (STA) may be allocated a portion of the channel bandwidth (unlike orthogonal frequency division multiplexing (OFDM) where each STA is allocated the entire channel bandwidth). As noted above, the allocated portion of the channel bandwidth is referred to as a sub-channel and includes a set of OFDM sub-carriers (a type of resource unit).